Electronics Forum / Basics / October 2005

I was curious, I have seen a number of devices which simply took a single
AAA battery as a power source(Rio MP3 player, some IR remotes etc..).
What is the technology behind these low voltage devices? I thought even HCT
CMOS needed 2 volts or higher?

I have an 18A continuous and 20A surge 13.8V power supply with just
screw terminals.  I plan to put it in a box with a power switch a meter
and a few banana plugs.  Problem is the highest current rating banana
plug I can find is 15A.  I see other power supplies that have a single ...

I recently posted about a bat detector (read ultrasonic pitch
downshifter) I'm building from the following schematic:
  http://home.kabelfoon.nl/~bertrik/bat/simphet.htm
My goal is to build it without the indicated coils. Bob Eldred

I have googled for freeware win32 software to make ASCII circuit diagrams,
but I can't seem to find such a ting.
Are there any good ones?
 erik

Alright... any help would be GLADLY appreciated... I'm trying to figure
out how to decide what diodes and transistors to use in projects...
what factors do I need to look at to make these decisions. thanks

I would like to make some easy experiments
with operational amplifiers.
Where to find easy experiments or circuits
(not theory) with operational amplifiers.

Greetings to all,
I was thinking about building low-cost analog sound level meter, however,
i am not sure how to get the non electrical value of sound pressure and
transform it in electrical value. I planned to display the level with

I need to get hold of a 1.5K trimmer pot for an old arcade game
monitor but cannot find one of this value anywhere. Seeing as it's
essential that I use 1.5K but the closest that I can find is 1K or
2.5K, is there any way that I could modify, for example, a 1K pot with

Anyone can help me, im new do things with electronics
I have a light modulate kit built with THYRISTOR´s and wen I try using
light with transformer (normal spots of 30W) they don't work, only
the normal lamp work.

I am trying to debug a kit that I bought that isn't working. I am
trying to test various links on the board with a an LED and resistor
soldered together.
When I hit the put the ends of the LED/resistor at a point on the board

I'm in a bind and I need a crimp for sealing shrink wrap.  I thought it
might be a fun little project and it should be easy, but I am very new
to electronics.  I think what I need is nichrome wire, but I don't know
what type.  Does anyone know if the nichrome wires are "live"?  in

I  hope no one will mind if I jump in and ask a bit of a beginner's
question.
The circuit below is from the first stage of an audio distribution switch.
Input will be 1V P-P over the audio range of 20-20K, but I am not well

I recently discovered this newsgroup and I think it's awesome. Thanks for
all the information posted.
I have a question regarding LED lighting on an HO scale model train.
I want to replace the headlight on the train with an LED. I was wondering if

I have a counter i want to increment with a normally open  output wire fro
a pnp sensor. When i activate the sensor the counter counts at a
incredible rate. Could anyone help me with this?

Okay, I will see if I can overstay my welcome in a hurry here :-)
Folks helped me with the first stage of a three stage audio circuit, and I
get the idea of what each one does, thanks to the NS app notes I was
referred to, but now what I am not getting is, what might be the purpose